Choke

ABSTRACT

A choke for the burner head in an oil-fired unit, comprising a cylindrical support adapted to fit over the orifice of an airsupply pipe, a flame-stabilizer funnel extending from the external rim of said support obliquely inwards, which stabilizer funnel, at its internal end, supports a turbulence-producing device having inclined blades and a central opening for an oil jet, the portion of the flame-stabilizer funnel which is adjacent to the support having an arcuate cross-sectional form whose tangent at the point of contact with the support makes an acute angle with said support, the flame-stabilizer funnel having a series of openings axially spaced from the turbulence-producing device and whose inner edges are offset radially outwards so that air jets passing through the openings are directed obliquely inwards.

United States Patent Gulliksson [4 51 Mar. 21, 1972 CHOKE 3,383,052 5/1968 Dysart et a1 ..431/265 x 72] Inventor: Karl Ivar Aka Gun 11, Norrkopingy 3,490,858 1/ l 970 Fletcher ..43 1/265 Sweden Primary Examiner-Carroll B. Dority, Jr. [73] Assignee: Sovereign Finanz A.G., Zurich, Switzer- 4101mm stem and 57 ABSTRACT [22] Filed: NOV. 2, 1970 [30] Foreign Application Priority Data Nov. 4, 1969 Sweden ..15076/69 [52] US. Cl ..239/490, 239/399,431/265,

, 431/351 [51] Int. Cl ..B05b 1/35 [58] Field of Search ..431/265, 350, 351, 352, 354; 239/399, 490

[56] References Cited UNITED STATES PATENTS 2,665,748 1/1954 Cornelius...

Appl. No.: 86,086

A choke for the burner head in an oil-fired unit, comprising a cylindrical support adapted to fit over the orifice of an airsupply pipe, at flame-stabilizer funnel extending from the external rim of said support obliquely inwards, which stabilizer funnel, at its internal end, supports a turbulence-producing device having inclined blades and a central opening for an oil jet, the portion of the flame-stabilizer funnel which is adjacent to the support having an arcuate cross-sectional form whose tangent at the point of contact with the support makes an acute angle with said support, the flame-stabilizer funnel having a series of openings axially spaced from the turbulenceproducing device and whose inner edges are offset radially outwards so that air jets passing through the openings are directed obliquely inwards.

9 Claims, 3 Drawing Figures PATENTEDMARZI x972 A K\\\\\\\\\ /IIIIIIIIIII4 INVENIDR.

KARL IVAR AKE GULLIKSSON.

CHOKE This invention relates to a choke forthe burner head in an oil-fired unit. I

It is a normal procedure to fit a choke to the burner head in an oil-fired unit, that is to say an air-throttle device consisting of inclined, stationary blades arranged to produce turbulence in the combustion air so that the air mixes thoroughly with the cone of oil mist coming from the oil-injector nozzle.

However, it has been found that said cone of oil mist may contain large oil droplets or agglomerations of oil droplets which cannot be completely burned without soot formation. Attempts have been made to counteract this by providing the opening of the burner head with a restriction and arranging a slot for admitting a secondary air supply inside and close to same. Although this arrangement secures a noticeable improvement, it does not completely prevent sooting.

The object of the present invention is to create a choke which completely prevents sooting and achieves sootless combustion at the expense of less surplus air.

The invention provides a choke for the burner head in an oil-fired unit, comprising a cylindrical support adapted to fit over the orifice of an air-supply pipe, a flame-stabilizer funnel extending from the external rim of said support obliquely inwards, which stabilizer funnel, at its internal end, supports a turbulence-producing device having inclined blades and a central opening for an oil jet, the portion of the flame-stabilizer funnel which is adjacent to the support having an arcuate cross-sectional form whose tangent at the point of contact with the support makes an acute angle with said support, the flame-stabilizer funnel having a series of openings axially spaced from the turbulence-producing device and whose inner edges are offset radially outwards so that air jets passing through the openings are directed obliquely inwards.

The invention will be further described, by way of example only, with reference to the accompanying drawings in which:

FIG. 1 is a choke viewed in the direction looking towards the burner mouth;

FIG. 2 is a partial radial section through the choke illustrated in FIG. 1; and

F IG. 3 is a side elevation of the choke illustrated in FIG. 1.

The choke in the drawing comprises a cylindrical support 1 arranged to fit over the orifice of an air-supply pipe 2 and a flame-stabilizer funnel l integral with the support 1 and extending from the rim of the orifice obliquely inwards, which stabilizer, at its internal end, supports a turbulence-producing device 11 with inclined blades 3 and a central opening 9 for an oil jet or nozzle (not shown).

The portion 4 of the flame-stabilizer funnel 10 which is located adjacent to the'support 1, has a circular arcuate crosssectional form whose tangent at the point of contact with the support 1 makes an acute angle of 45 to 65, preferably 55, with said support. The section 4 merges into a cylindrical section 5 which in turn merges into a conical funnel-shaped section 6 carrying the blades 3. immediately outside said cylindrical section 5, the flame-stabilizer funnel carries a series of uniformly distributed, preferably circular, openings 7 whose inner edges 8 are offset radially outwards so that the air jets exiting through the openings are directed obliquely inwards and contribute to producing extremely fine division of the oil mist coming from the oil jet, and to the combustion of oil particles which have not been burnt in the air flow coming from the blades 3 of the turbulence-producing device.

lt has been found expedient to make the cylindrical section 5 of the flame-stabilizer funnel 10 the same length axially as the section 4, and to give the flame-stabilizer funnel 10 an axial dimension which is between 40 and 50 percent, preferably 45 percent, of its external diameter.

The present invention has made it possible to increase the pressure of the air 60 percent and to decrease the pressure of oil percent without any risk: for blowing out the flame, and to obtain a fully sootless combustion with 12-14 percent carbon dioxide in the resulting gases at all loads. t

I claim:' l. A choke for the burner head in an oil-fired unit, comprising a cylindrical support adapted to fit over the orifice of an air-supply pipe, a flame-stabilizer funnel extending from the external rim of said support obliquely inwards, which stabilizer funnel, at its internal end, supports a turbulence-producing device having inclined blades and a central opening for an oil jet, the portion of the flame-stabilizer funnel which is adjacent to the support having an arcuate cross-sectional form whose tangent at the point of contact with the support makes an acute angle with said support, the flame stabilizer funnel having a series of openings axially spaced from the turbulenceproducing device and whose inner edges are offset radially outwards so that air jets passing through the openings are directed obliquely inwards both axially and radially and towards said central opening for the oil jet.

2. A choke as claimed in claim 1 in which said openings are circular and are uniformly distributed around the flame-stabilizer funnel.

3. A choke as claimed in claim 1, inv which the axial length of the flame-stabilizer funnel is between 40 and 50 percent of its external diameter.

4. A choke as claimed in claim 3 in which the axial length of the flame-stabilizer funnel is 45 percent of its external diameter.

5. A choke as claimed in claim 1 in which the tangent at the junction of the arcuate section of the flame-stabilizer funnel with the support makes an angle of 45 to65 with said support.

6. A choke as claimed in claim 5 in which said angle is 55".

7. A choke as claimed in claim 1 in which the flame-stabilizer funnel comprises said portion adjacent to the support a cylindrical portion integral with said portion adjacent to the support, and a conical portion integral with said cylindrical portion and supporting said turbulence-producing device.

8. A choke as claimed in claim 7 in which the cylindrical portion has a length substantially the same as that of the said portion adjacent to the support.

9. A choke as claimed in claim 7 in which said openings are arranged in the portion adjacent to the support immediately next to where said portion merges into the cylindrical portion. 

1. A choke for the burner head in an oil-fired unit, comprising a cylindrical support adapted to fit over the orifice of an airsupply pipe, a flame-stabilizer funnel extending from the external rim of said support obliquely inwards, which stabilizer funnel, at its internal end, supports a turbulence-producing device having inclined blades and a central opening for an oil jet, the portion of the flame-stabilizer funnel which is adjacent to the support having an arcuate cross-sectional form whose tangent at the point of contact with the support makes an acute angle with said support, the flame-stabilizer funnel having a series of openings axially spaced from the turbulence-producing device and whose inner edges are offset radially outwards so that air jets passing through the openings are directed obliquely inwards both axially and radially and towards said central opening for the oil jet.
 2. A choke as claimed in claim 1 in which said openings are circular and are uniformly distributed around the flame-stabilizer funnel.
 3. A choke as claimed in claim 1, in which the axial length of the flame-stabilizer funnel is between 40 and 50 percent of its external diameter.
 4. A choke as claimed in claim 3 in which the axial length of the flame-stabilizer funnel is 45 percent of its external diameter.
 5. A choke as claimed in claim 1 in which the tangent at the junction of the arcuate section of the flame-stabilizer funnel with the support makes an angle of 45* to 65* with said support.
 6. A choke as claimed in claim 5 in which said angle is 55*.
 7. A choke as claimed in claim 1 in which the flame-stabilizer funnel comprises said portion adjacent to the support a cylindrical portion integral with said portion adjacent to the support, and a conical portion integral with said cylindrical portion and supporting said turbulence-producing device.
 8. A choke as claimed in claim 7 in which the cylindrical portion has a length substantially the same as that of the said portion adjacent to the support.
 9. A choke as claimed in claim 7 in which said openings are arranged in the portion adjacent to the support immediately next to where said portion merges into the cylindrical portion. 